1. Field of the Invention
The present invention relates to systems and method of supplying electrical power to motherboards, such as may be used in server applications.
2. Description of the Related Art
Industry hardware manufacturers, led by Intel, have formed a Server System Infrastructure (SSI) consortium, to develop design standards for servers, much like those characteristic of desktop PCs. A stated goal of the SSI consortium is to enable future server market growth by standardizing interfaces between components including boards, chassis, and power supplies and by developing common server hardware elements. SSI has made an effort to develop a set of standards for server power supplies and motherboard bays.
One industry standard server configuration adopted under SSI includes one or more power supplies per electronic server bay. SSI standard documentation describes power supplies and server motherboards with signaling, power architecture and sequencing to accomplish this configuration. FIG. 1 is a schematic diagram of a conventional system configuration 10 according to the SSI standard, wherein a single power supply 12 is used to power a single motherboard 14. In a power-on sequence, alternating current (AC) is first applied at an AC input 16, providing five volts (“+5Vsb”) to the motherboard 14 by way of a standby regulator 18 included with the power supply 12. A micro-controller 20 included with the motherboard 14 may go through some diagnostics before asserting a power-on signal “PSON#” to the power supply 12. The main power section 15 of the power supply responds to the PSON# signal with a “PWOK” (i.e. power OK) signal to inform the microcontroller that it has turned on the main power in the power supply 12. Turning on the main power in this manner provides power to the rest of the server motherboard 14. Bulk voltage outputs +12V, +5V, +3.3V, and −12V feed a main processing section 24 of the motherboard 14 that includes, for example, as processors (e.g., CPUs), memory (e.g., DIMMs), and applications cards (e.g., PCI cards). This specification reliably powers-up the single motherboard 14 with the single power supply 16.
However, current SSI standards do not provide much flexibility in configuring new server systems, even though server technology is still rapidly changing and server power management is more important that ever. A solution is desired to increase the flexibility of configuring power supplies and servers while maintaining consistency and compatibility with current SSI server and power supply standards.